The present invention relates to a method as defined in claim 1 and as a system as defined in claim 10.
This invention relates to a method and system for preventing the initial onset and further development of trailer oscillations and swaying (“Snaking”) movements, which commonly occur when towing a trailer, caravan, boat or similar nonautomotive vehicle behind an automotive powered vehicle. The automotive powered vehicle may have a power plant of either a petrol engine, diesel engine, electric motor or hybrid nature.
The term trailer as used in this description refers to any wheeled device that is attached to and can be removed from a suitably powered towing vehicle. A trailer may be used for moving a boat or car from one location to another. A further embodiment of a trailer as described in this invention could include a horsebox trailer used for moving a live horse from location to location. Other embodiments may include a caravan, which may be towed from location to location whilst on touring holiday or trip. One further embodiment of a trailer may include a wheeled device used for moving large volumes of goods from location to location. Clearly, the term trailer can refer to any number of different embodiments of a device with an axle or multiple axles and wheels or multiple wheels used for a wide range of purposes; the constant similarity between any of these trailers is that they are attached and detached from a powered towing vehicle as defined above.
An increasing number of serious towing related accidents occur each year across the world due to the onset and development of trailer oscillations and swaying (“Snaking”) movements, which the driver of the towing vehicle is unable to control and cease. The proliferation of these oscillations, also known as “Snaking” based accidents that occur each year are increasing fundamentally due to the growing popularity of towing based sporting activities and holidays.
In the United Kingdom, persons holding a license issued prior to 1 Jan. 1997 may usually drive a vehicle and trailer with a combined maximum authorised mass (MAM) up to 8,250 kg, which is approximately 8 (eight) imperial tons. Persons with license issued after 1 Jan. 1997 may drive a vehicle and trailer combination with a combined maximum authorised mass (MAM) up to 3,500 kg, which is approximately 3.4 (three point four) imperial tons. These substantial limits allow persons with limited or no previous training or experience to tow trailers of a considerable mass and thus momentum. A sizeable momentum is often one of the main contributing factors in oscillation (“Snaking”) based towing accidents.
Presently, the majority of stabilizing based systems appear to be based around microcontroller software based detection systems which attempt to reduce and stabilize the trailer after the oscillations (“Snaking”) movements have developed fully in both the trailer and towing vehicle. The systems then appears to rely upon slowing both the trailer and towing vehicle simultaneously. These systems slow the towing vehicle immediately by applying braking actions to both the vehicle being used to tow the trailer and in some cases also the trailer itself (if it posses fully controllable brakes) simultaneously. Often, in some more basic set-ups, the application of overrun (surge) brakes if fitted to the towed nonautomotive vehicle (trailer) are applied by the oscillation force itself. This basic system, although commonly found, does not allow for any monitored and controlled braking force on the trailer.
The present invention relates to a method and system and device for preventing the initial onset and further development of trailer oscillations and swaying (“Snaking”) movements at the very initial inception of the digitally detected and monitored oscillations. The system utilizes an FPGA (Field Programmable Gate Array) based detection, monitoring and control system with a Mesh network of Bluetooth Low Energy (BLE version 5.0 onwards) IMUs (Inertial Measurement Units) sensors located on both the trailer (nonautomotive vehicle) and the towing vehicle (automotive vehicle). The use of the FPGA digital hardware based technology allows for at least one order of magnitude (10×) speed increase within the detection, monitoring and control system over software based microcontroller systems. The system utilizes a Kalman filter algorithm within the hardware of the FPGA to reduce noise within the IMUs sensor data prior to processing. The system then runs its own specific algorithm using the multiple IMU's data to detect the initial onset of trailer and towing vehicle oscillations and swaying (“Snaking”) movements. Once the FPGA hardware based algorithm has detected the initial onset of oscillations and swaying (“Snaking”) movements the system then detects if it is safe to initiate its oscillation and swaying (“Snaking”) reduction procedure.
A brief overview of the basic oscillation and swaying (“Snaking”) procedure will now be explained prior to drawings being discussed and an in-depth explanation being given in full later. The system, once it has detected the very initial onset of oscillations and swaying (“Snaking”) movements within the IMUs data from either and/or both the trailer and towing vehicle; the system's hardware based FPGA and Dual ARM Cortex-A9® processors will undertake the following procedures. The system will if possible detect by communicating with the vehicle's CAN Bus if it is safe to increase vehicle speed. The system will do this by requesting information from the towing vehicle's LIDAR (Light Detection and Ranging) Cruise Control System (or equivalent system) if available via the CAN Bus Network; if this information is not available then the driver of the vehicle will be required to actuate a paddle control or button on the steering wheel surround subsequent to a beeping noise within the cabin area of the towing vehicle. Assuming that the system has received information either from LIDAR or driver that it is safe to initiate the procedure it will immediately commence its procedure as follows.
The system will initially apply a low duty cycle PWM (Pulse Width Modulation) driving signal in the region of 35% to both of the trailer actuators (left and right) so as to apply a small amount of braking force of around 35% to the trailer or towed nonautomotive vehicle. Simultaneously, the system will increase the towing speed of the towing vehicle having already ascertained that it is safe to do so by either LIDAR or driver intervention as discussed above. The increase in road speed will be in the region of 10% of the previous road speed. The system will then wait a short amount of time, in the region of 250 ms to 500 ms (two-hundred and fifty milliseconds to five-hundred and fifty milliseconds) prior to analysing once again the signals from the IMUs. The four signals from the IMUs, or more if a greater number of IMUs are fitted to the trailer; will once again be analysed through a Kalman filter using the hardware FPGA as previously detailed above. Trailers having a longer wheelbase, which may have an additional number of axles may require an additional number of IMUs to be mounted on the trailer located around a line that traverses the wheels of the additional axles. Once the filtered signals have been compared within the original signals prior to the brake signals being applied (brake application on trailer only) and the road speed increased of the towing automotive vehicle, a decision will be made to either incrementally increase the braking PWM signal pulses and speed further, or to remain as is, or decrease. The decision will be made based on either the oscillations and swaying (“Snaking”) movements increasing or decreasing. A detailed description of this procedure will be given after the drawings have been discussed in detail.
The major advantage of this invention and method is that oscillations and swaying (“Snaking”) signals received from the IMUs are processed in real-time with a Kalman Filter in hardware (FPGA). The processing of at least four separate channels or more of IMU's data is being undertaken in parallel execution within the FPGA's hardware and not being processed sequentially as it would if it was being processed within a Micrcontroller's CPU within a software algorithm. The FPGA hardware's processing speed advantage is at least an order of magnitude (10×) faster than in software within even one of the fastest Microcontroller's currently on the market presently.
The present embodiment of the invention utilizes a ZYNQ 7000® series SoC FPGA. This particular FPGA allows for a combination of both Field Programmable Gate Array (FPGA) type hardware with a Dual Core ARM Cortex-A9 Processors with each core running at a speed of up to 1 GHz. This particular FPGA is manufactured by Xilinx®, however a similar embodiment of this invention could be produced with a similar FPGA with either a Single or Dual Core ARM Cortex Processor from another manufacturer such as Altera®, Actel® or Lattice Semiconductor® to name just a few possible alternatives.
The present embodiment which utilizes the ZYNQ 7000® series SoC FPGA with its Dual ARM Cortex-A9 Processors allows for a processing speed increase of at least an order of magnitude (10×) greater than any other Microcontroller software based system. The ZYNQ 7000® series also offers the advantage of the “AXI” (Advanced eXtensible Interface) connection between the Programmable Logic of the FPGA and the Processing System of the Dual ARM Cortex-A9 Processors. These hardware and software link advantages allow the present invention to process and control the trailer oscillations and swaying (“Snaking”) movements in virtually real-time so as to be able to control and stop the oscillations (“Snaking”) at its onset prior to its further development into enlarged oscillations which otherwise may develop further without the ability to curtail them.
The present invention offers a number of other safety advantages over other anti oscillation (“Snaking”) systems currently on the market. These briefly include a GPS communications module that allows a database of oscillation (“Snaking”) prone areas (known as “black spots”) to be logged and catalogued for future safety advice. The system also incorporates an emergency braking system for the trailer, so that in the event of the trailer becoming detached from the towing vehicle the brakes will automatically and immediately be applied to the trailer and the hazard and braking lights will instantly be applied. The hazard and braking lights on the trailer will be powered from the rechargeable batteries of the wireless electric brake actuators; this will be described in more detail later in the description. These and further additional safety features will be discussed in more detail after the description of the drawings in the detailed description that follows.